There are five specific long-term aims for this research plan: (1) The first aim is to test an animal model for studying the effects of drugs on cognitive functioning. Maier's 3-table reasoning apparatus will be used for testing the ability of rats to integrate information learned in one chemical state with information learned in another chemical state to solve a spatial location problem for a food reward. Research has shown that the processes involved in solving this problem are different from those involved in most learning tasks which depend upon the association of contiguous events (Maier, 1932a; Stahl & Ellen, 1974). (2) The second aim is to establish the classes of drugs for which this phenomenon occurs. Both non-prescription drugs and controlled substances will be studied. It is hypothesized that state-dependent performance occurs for drugs such as caffeine and nicotine as well as for abused controlled substances such as morphine and methadone. (3) A third aim is to determine if state-dependent performance under one drug (such as morphine) can be blocked by another drug (such as naloxone) or whether the drug and blocker combination form what is essentially a third chemical state. (4) A fourth aim is to initiate several pilot studies to develop an operant conditioning research paradigm that includes some of the features that make the Maier 3-table problem unique. Subjects will receive a visual or an auditory cue and be required to identify the appropriate cue set, or perhaps a cue sequence, necessary for a food reward. (5) A fifth aim is to train minority undergraduate students in the research methods used in behavioral psychopharmacology to prepare them for graduate training in a mental health research field.